This relates basically to graphics processing and, particularly, to rendering micropolygons.
A geometric primitive may be split into smaller primitives several times until its screen space size is small enough, with frustum culling occurring at each stage. In addition, inside each tile of a screen, front to back sorting of the primitives may be done and each primitive may be occlusion culled against a hierarchical depth buffer. The splitting loop is executed until the input primitive has been divided into many small parts, and the screen space extents of each part is less than a user controlled threshold.
Dicing occurs next, where each sub-primitive is uniformly tessellated into a grid of sub-pixel sized quads or triangles called micropolygons. Each micropolygon is view frustum and back face culled. A micropolygon is a rendering primitive smaller than a pixel. It may, for example, be a quadrilateral or a triangle.
Displacement mapping may occur, where the displacement shader is executed per vertex in the grid.